Assessment of the abundance of Culicoides chiopterus and Culicoides dewulfi in bovine dung: a comparison of larvae extraction techniques and emergence traps.

We compared two larvae extraction methods involving sugar-flotation and an adapted Berlese funnel-extraction with emergence traps. This was done in order to analyse the colonisation of cowpats by Culicoides chiopterus (Meigen 1830) and Culicoides dewulfi (Goetghebuer 1936) (Diptera: Ceratopogonidae) and to gain information on the comparability and efficacy of these three methods. With all three methods, a considerable number of individuals was obtained. Significantly more individuals were obtained via sugar-flotation and Berlese funnel-extraction compared to the emergence traps. These differences, likely due to natural mortality and sample processing are discussed. We recommend Berlese as an efficacious method for extracting Culicoides larvae from bovine dung. It produces data rapidly and extracted larvae are viable. In comparison with Berlese, slightly more larvae were obtained by sugar-flotation, but this method was very labour intensive.